This invention relates to noise and interference in radios, electronic communication devices and telephones. These items can only have noise reduction circuits placed in the interior of the radio, etc. Doing this disturbs the internal wiring and in some instances detunes the internal circuits and leaves a large part of the internal noise generating circuits free to continue to generate noise. The ideal solution would be to have such noise reduction and interference rejection circuitry placed outside the radio and control all the noise at the earphone or speaker connections and contribute no noise or interfering signals on its own and not require a power supply for operation.
This invention meets all of these requirements, not installed inside the radio or other audio equipment, and does not contribute noise or interference while removing noise and interference and uses well known electronic parts available from any electronic parts store to accomplish this noise reduction, elimination. The first working model of this invention was completed May 22, 1996.
None of the parts are invented by me to make this noise controller work. The invention is made possible by combining these well-known and readily available parts connected in a manner that I have never seen in the twenty odd years of searching for a circuit that would do the very things I have outlined above.
Description of Prior Art
Transmission line transformers utilize ferrite transformer core materials to achieve a wide-band pass transformer to cover various sections of the electromagnetic spectrum, such as the audio frequency range. It is possible to construct a circuit using transmission line type transformers with two distinct circuits using one transformer and one variable resistor without using the same common return or ground.
An examination of FIG. 1 shows the circuit developed by me. This was the basis of the search for comparable art. If any connection of these windings and the variable resistance other than shown here are made the circuit does not work at all. Therefore, comparable art has to be exactly as shown and none has been found. If such art exists, it is a closely held secret and not available in publications.
An article in the proceedings of the IRE written in the 1950's pertaining to wide band baluns using ferrite and powdered iron cores with side-by-side winding or bi-filar, twisted pair of wires for wide band matching transformers between co-axial cable and center fed antenas providing a balanced feed system and eliminating the skew from unbalanced termination of coaxial cable was read frequently to understand the implications of this technology.
The detailed discussion of ferrite cores doped with several minerals having magnetic properties at high frequencies (rf) and the close coupling of two windings using the bi-filar method of creating balanced windings was to be the solution to winding two wires of the same length on the ferrite toroid and having a balanced set of windings that did not require the addition of or the removal of wire to achieve an electrical phase balance.
In addition to the discussion of the unique property of ferrite cores to maintain all the phase angles at any point on or in the core and that the flux was contained close to the core, this article ultimately held the key to having a common signal return or ground separate from the input common or ground. Therefore since none of the invention requires the inventing of any or all parts of the physical device, only the connection of the toroid and variable resistor is new and to my best knowlege does not exist outside of my mind and such disclosures as have been made to secure a patent. There is no comparable Art.
The assembly of the parts, all well-known electronic parts, in themselves do not constitute the basis of the patent, it is the connections made between these parts and the toroid and variable resistance (see FIG. 1.) The phase reversal of the two windings into independant circuits in a manner not done, to my knowledge, by anyone. The toroid and variable resistance as wired constitutes the basis for a patent. The application has been included to illustrate the method of achieving the noise control and suppression of interference.
Additional proof of no prior art is this--in operation the signal is divided into positive and negative phase angles. The separation occurs at point Lc (FIG. 1) also known as the reversal point which occurs between the two windings which are connected at the 180 degree point on a sine wave. This point becomes a common return for the output circuit. Connected across the input side of the transformer is a variable resistor, in the form of a wire wound potentiometer. The wiper arm becomes the signal side of the output circuit. A load placed between the wiper arm and the phase center tap Lc is now the output with the common ground at 180 degrees from each side of the two coils on the transformer. An out of phase signal corresponding to the phase of each winding makes it possible to have 180 + or - on each side of the output common.
Being able to invert each side of the transformer phase angles of 180 degrees + or 180 degrees - allow cancellation to take advantage of the Upper sideband (+) and the Lower sideband (-).
The 180 degree complete cancellation point occurs at the approximate center position of the variable resistor and is marked by complete silence.
Commercial cancellation systems in use today are based upon an all or nothing 180 degree out of phase signal being overlaid on the signal and the only variation being the use of a volume control to control the amount of cancellation based on amplitude control rather than variable phase control. The other method used is to have two microphones placed in earphones to pick up local noise, electronically phase them for 180 degree opposition with a fixed degree of cancellation and fixed or adjustable volume and fed back to the earphones as well as to a telephone. (I have purchased a set of the above method of canceling noise and found it did not have much effect beyond five hundred cycles). This item has been removed from their current catalog.
Recognized methods of removing noise are: Fm modulation, digital processing, various filters, compandering, pulse coded processing and variations of these methods, all suffering from the same problem. In the above noise reduction methods they fail as the signal strength fades below the threshold level where limiting begins.
My invention continues working until there is no signal decernable above the noise or in the noise. This is so because of the lateral movement of the canceling wave form.
Therefore, there is no applicable art except that art relative to the parts themselves but not to my method of connecting the parts to make the whole operate as stated above.
The Objects and Advantages.
My invention takes controlling noise and interference to a level where signals can be recovered when barely audible without contributing noise of its own and without the need for a d.c. power supply.
Another object and advantage of my invention provides an adjustable method of lateral phase cancellation noise control in electronic communications. The advantage lies in the ability to use this design to remove noise or interference from any signal provided it relates to a 360 degree phase angle as decoded by the receiver. Other advantages are:
a. only two major components and two minor componets are required. PA1 b. no direct voltage or current is needed to power the equipment of my invention. PA1 c. no common ground buss is used, input signal and output signal have their own. PA1 d. control of phase angle is continous from zero to 360 degrees. PA1 e. changing one or both components the device is usable form one cycle to the upper limits of signals in electronic communications. PA1 f. if a coherent waveform exists it can be rescued from high incoherent noise levels. PA1 g. signal loss in a reflected signal is less than 0.25 dB (signal reflected back to source.) PA1 h. my invention has been reduced to practice, undergone testing and is ready to manufacture. PA1 i. every old radio whether tube, transistor, crystal set as well a near obsolete electronic communications equipment will have, with my device, low or no noise and be useful again. PA1 j. most beneficial will be the elimination of ear numbing noise. PA1 The universal noise controller is neither input or output dependent on a commn ground with the device it is connected to. PA1 The method of cancellation is continously variable with lateral cancellation from 0 to 360 degrees. Current devices are all or nothing. PA1 The low weight (about 10 ounces) provides true portability. PA1 Rural areas will find my device indispensable in telephonic and radio communications. PA1 A safety point--the unit can be hooked up backwards and still provide communications. PA1 The noise elimination will not be as complete but communications will pass through.
Further Objects and Advantages: eliminating the need for a power supply extends the usefulness of the device to applications where an additional power sources would preclude its use in a portable application.